Signs of weak imaan:

1) Committing sins and not feeling any guilt
2) Having a hard heart and no desire to read the Quraan
3) Feeling lazy to do good deeds, e.g. being  late for salaat
4) Neglecting the Sunnah
5) Having mood swings, for instance being upset about petty things and
   being bothered and irritated most of the time.
6) Not feeling anything when hearing verses from the Quraan, for    instance
   when Allah warns us of punishments and his promise of glad tidings.
7) Finding difficulty in remembring Allah and making zikr.
8) Not feeling bad when things are done against the Shariah.
9) Having a desire for status.
10) Being mean and miserly, i.e. not wanting to part with health.
11) Ordering to do good deeds when we are not practising them     ourselves.
12) Feeling pleased when things are not progressing for others.
13) People bothering about whether something is haram or halal only;     and
    not avoiding makhru (not recommended) things.
14) Making fun of people who do simple good deeds, like cleaning the
    mosque.
15) When not feeling concerned about the situation of muslims.
16) Not feeling the responsibility to do something to promote islam.
17) Being unable to deal with calamities, for instance crying and     
yelling
    in funerals.
18) Liking to argue just for the sake of arguing without any proof.
19) Becoming engrossed and very involved for dunyah, i.e. wordly     things,
    for instance feeling bad when losing something in terms of     material
    wealth.
20) Becoming engrossed and obsessive in ourselves

LISTED BELOW ARE WAYS TO INCREASE OUR IMAAN:
1) Recitation and pondering on the meanings of the
   Quraan.
   Tranquility then descends and our heart becomes
   soft. To get optimum
   benefit, remind ourselves that Allah is speaking
   to us. People are
   described in different categories in the Quraan;
   Think in whiCH of them do we find ourselves
2)Realise the greatness of Allah. Everything is under
  his control. There are signs in everything we see that points us to
  his greatness.
  Everythings happen according to his permission.
  Allah keeps track and
  looks after everything, even a black ant on a blact
  rock ina dark
  moonless
  night.

3) To make an effort to gain knowledge, at least the
   basic things in daily
   life e.g. how to make the wudu properly. To know
   the meaning behind
   Allah's name and attributes. People who have
   taqwah are those who have
   knowledge.

4) To attend gatherings where Allah is remembered. In
   such gatherings we
   are surrounded by angels.

5) We have to increase our good deeds. One good deed
   leads to another good
   deed. Someone who gives charity, Allah will make
   way for him or her to
   do good deeds easy  for that person. Good deeds
   must be done
   continuously, not in spurts.

6) We  must fear a miserable end of our life; the
   rememderance of death is
   the destroyer of pleasures

7) To remember the different levels of akhirah, for
   instance when we are
   put in our graves, when we are jugded, whether we
   are in paradise or
   hell.

8) Make duah, realise that we need Allah. Be humble.
   Not to have much
   hope for wordly things in this life

9) Our love for Subhanahu Wa Ta'Allah must be shown
   in actons. We must
   hope Allah will accept our prayers, and be in
   constant fear that we do
   wrong. At night before going to sleep, we must
   think what good did we do during the day.
10) Realise the effects of sins and disobediance- ones
    imaan is increased
    with good deeds and our imaan is decreased by bad
    deeds. Everything
    that happens is because Allah wanted it. When
    calamity befalls us-
    it is also from Allah. It is a direct result of
    our disobediance to
    Allah.